In the construction techniques, a pre-casting method is usually adopted in order to save construction time. In the pre-casting method, the components, such as beams, columns, and decks, are pre-casted off the construction site and are then transported to the construction site for subsequent assembling and grouting. Accordingly, the space at the construction site would be less taken up and support frames used for construction would be greatly reduced. Therefore, the working flow line would be much better. The on-site construction time would be significantly reduced. Since the beams, columns, and decks are produced in the workshop, away from the construction site, the production rate, precision and quality thereof can easily be monitored and reach the expected level. Accordingly, the pre-casting method has become the mainstream for the current construction technology.
Grid decks are widely used in the construction of plants, particularly, those for a wafer factory. Grid decks can be produced on-site through grouting or in a pre-casting workshop. The grid decks contain rebar, which reinforces the strength thereof. The grid decks also have hollow portions which effectively reduce the weight thereof.
When building a plant, the pre-cast grid decks are laid over the pre-cast columns in a suitable span so that on-site construction is simplified, and thus the construction time is significantly reduced.
A normal grid deck assembly is shown in FIG. 1. The connecting bars 71, 81 protrude from the sides of the grid decks 70, 80, respectively. The connecting bars 71, 81 further connect the lap-joint bars 91. When grid decks are paved, they are laid on the I-beam 60 with gaps therebetween. Grout is filled into the gaps formed between the grid decks 70, 80. After the grout is cured, the grid decks 70, 80 will be connected to each other and fixed.
The gaps between grid decks 70, 80 can be too small so that the overlap length between the lap-joint bars 91 and connecting bar 71 or 81 can be too short and the strength created by the lap joint can be insufficient after the grout is cured. Although the strength can be increased when more connecting bars and lap-joint bars are provided or the width of the gap between the I-beam is used, these two methods will cause an inconvenience to the on-site construction and pre-cast production and make the costs higher. To overcome these problems, an improved method is provided, in which a recess 24, 34 is created on each of the grid decks 20, 30 to be connected as shown in FIG. 2. Connecting bars 21, 22, 23 and connecting bars 31, 32, 33 protrude from grid deck 20 and 30, into the recess 24, and 34, respectively. Connecting bars 21, 22, 23 and connecting bars 31, 32, 33 are connected by a lap-joint bar 50. Grout is filled in the gap between the grid decks to be assembled. With the recesses 24, 34, the gap between grid decks 20, 30 is wider than that without recesses. The wider gap makes the contact area between the connecting bars, the lap-joint bars and the cement (grout) larger, and thus the strength of connection between the grid decks would be increased.
The grid decks with a recess still have the problem of insufficient depth of the recess in some occasions, and when the width of the I-beams is small, there is also a problem of insufficient gap width between the grid decks, which thus causes insufficient connection strength between the grid decks. Accordingly, there is a need to improve the connection of the grid decks.